洛谷 P1605 迷宫(dfs + 回溯)

https://www.luogu.org/problem/P1605

从起点到终点有多少种不同的方案

 

// luogu-judger-enable-o2
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <queue>
#include <vector>
#include <cstring>
#include <map>
#define mem(a) memset(a,0,sizeof(a))
using namespace std;
typedef long long lll;
const int maxn = 200005;
const lll INF = 0x3f3f3f3f3f;
int vis[6][6],vis2[6][6],ans;
int dir[8][2]= {0,1,0,-1,1,0,-1,0,-1,-1,1,-1,-1,1,1,1};
int dir2[4][2]= {0,1,0,-1,1,0,-1,0};
bool flag;
int n,m,t,ex,ey,sx,sy;
void dfs(int x,int y)
{
    if(x == ex&&y == ey)
    {
        ans++;
        return ;
    }
    else
    {
        for(int i=0; i<4; i++)
        {
            int fx = x + dir2[i][0],fy = y + dir2[i][1];
            if(fx>=1&&fx<=n&&fy>=1&&fy<=m&&vis[fx][fy]==0&&vis2[fx][fy]==0)
                {
                    vis2[x][y]=1;
                    dfs(fx,fy);
                    vis2[x][y]=0;
                }
        }
    }
}
int main()
{
    cin >> n >> m >> t;
    
        cin >> sx >> sy >> ex >> ey;
        mem(vis);
        mem(vis2);
        int x,y;
        for(int i=0; i<t; i++)
        {
            cin >> x >> y;
            vis[x][y] = 1;
        }
        if(vis[ex][ey] == 1)
        {
            cout << "0" << endl;
        }
        else{
        dfs(sx,sy);
        cout << ans << endl;
        }
    return 0;
}